a bad CPU + great GPU = good video game performance, even if overall raw performance is stuff because of CPU holding it back. it doesn't tell your overall performance because the CPU isn't the one rendering the game.
also GTA IV eh
the cpu is a big part of games actually. take bf3 for example, seemingly a game which relies way greater on the GPU then the CPU
tested out the following things. got a G530 celeron and a i7 3770. both LGA 1150. 7770 for the GPU. with the celeron, i was able to play on minimum with an average of 20 FPS. with the i7, medium settings at 60 FPS. for ram, 800mhz vs 1600mhz affected around 15 FPS. 5400 vs 7200 RPM hard drive, loading speeds around 15 seconds apart.
typically in the best setup, the GPU should be the bottleneck not the CPU